The present invention relates to extensively amorphous butene-1-propene-ethene terpolymers.
Extensively amorphous polyolefins are required in various fields of use, for example for sealing sheets for roofs and other purposes, for coating compositions and sealing compounds, and for filling compounds and adhesives.
It is known from DAS (German Published Application) No. 2,306,667 (equivalent to British Pat. No. 1,449,316) to produce extensively amorphous butene-1 polymers using the low-pressure method by the polymerization of butene-1, optionally in the presence of 0.1-30% by weight, based on the amount of butene-1, of other olefins, in solution, at temperatures of 40.degree.-120.degree. C. using a mixed catalyst of TiCl.sub.3 .multidot.n AlCl.sub.3 (n=0.2-0.6) and a trialkyl aluminum. These butene-1 polymers are very highly suited for many uses, but do have a softening point of 60.degree.-85.degree. C. which is too low for several areas of application, such as roofing sheets and other sealing sheets, for example. For such uses, amorphous polyolefins having softening points of 90.degree.-130.degree. C. are necessary.
Although extensively amorphous polypropylene exhibits higher softening points, it has not been possible heretofore to produce an extensively amorphous polypropylene in a simple and economical manner. Since, in addition to amorphous polypropylene, partially crystalline polypropylene is obtained in all cases, which latter is insoluble in hydrocarbons, polymerization in solution is impossible. A suspension of partially crystalline polypropylene in a highly viscous solution of amorphous polypropylene is always the result. This highly viscous solution and suspension can be controlled only with very great difficulty from the viewpoint of agitating technology. The removal of heat during polymerization also causes very great difficulty. Furthermore, the separation of the insoluble, partially crystalline polypropylene from the highly viscous solution presents an additional problem.
Co- and terpolymers of propene having a high propene content also show increased softening points, but the same difficulties occur during their production as do in the manufacture of extensively amorphous polypropylene. Additionally, incrustations occur during the polymerization of extensively amorphous polypropylene as well as of co- and terpolymers of propene having a high propene content, making the process very difficult and requiring regular cleaning operations. Therefore, there is still a need for extensively amorphous olefin polymers having softening points of 90.degree.-130.degree. C. whose production avoids such problems.